void DrawContour(){
    // TFile* file = new TFile("pLambda_h2_chi2_v6.scale4.interpolation.err.root","read");
    // TFile* file = new TFile("pLambda_h2_chi2_v6.scale4.interpolation.root","read");
    TFile* file = new TFile("pLambda_h2_chi2_v6.scale5.interpolation.root","read");
    auto c1 = (TCanvas*)file->GetObjectChecked("c_chi2","TCanvas");
    auto h2 = (TH2D*)c1->GetPrimitive("h2_chi2");
    double min = h2->GetMinimum();
    cout<<"min="<<min<<endl;
    // double contour[3];
    // double contour[2];
    double contour[1];
    contour[0] = min+1;
    // contour[1] = min+4;
    // contour[2] = min+9;
    // h2->SetContour(2,contour);
    h2->SetContour(1,contour);
    h2->SetLineColor(1);
    h2->SetLineWidth(1);
    TCanvas* c2 = new TCanvas("c2","c2",1800,1800);
    h2->Draw("cont3 same");
    // c2->Print("Contour_v6.err.png");
    c2->Print("Contour_v6.scale5.png");
}
